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Biomedical subjects

R M Overstreet

Publications and source records attributed to R M Overstreet.

50 records · Page 3Linked to original sources

Spirocamallanus cricotus sp. n. and S. halitrophus sp. n. (Nematoda: Camallanidea) from fishes in the northern Gulf of Mexico.

Spirocamallanus cricotus sp. n. (= S. pereirai, in part) and S. halitrophus sp. n. are described from marine fishes of the northern Gulf of Mexico. Spirocamallanus cricotus has a ledge anterior to the basal ring in the buccal capsule, similar spicules with a ratio of 1:1.4 to 2.1, 3 pre- and 5 postcloacal papillae, and 8 rectal glands in the female; S. halitrophus lacks the ledge and possesses dissimilar spicules with a ratio of 1:1.3 to 1.8, 3 pre- and 6 postcloacal papillae, and 4 rectal glands in the female.

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Poecilancistrium caryophyllum and other trypanophynch cestode plerocercoids from the musculature of Cynoscion nebulosus and other sciaenid fishes in the Gulf of Mexico.

Examination of over 3,000 fish, all sciaenids, has shown that plerocercoids of Poecilancistrium caryophyllum infect Cynoscion nebulosus, Bairdiella chrysura, Sciaenops ocellata, C. arenarius, Micropogonias undulatus, and Pogonias cromis in Mississippi Sound. In addition to P. caryophyllum, a pseudophyllidean-like trypanorhynch also infected C. nebulosus and M. undulatus. Pseudogrillotia pleistacantha selectively infected large P. cromis, Pterobothrium heteracanthum infected M. undulatus, and Pterobothrium lintoni infected Menticirrhus americanus. Prevalence and intensity of infections of P. caryophyllum in C. nebulosus from Mississippi, roughly 40% of the fish each possessing an average of about two worms, compare with infections observed in fish from Texas and Louisiana. However, values for fish from Apalachee Bay, but not Tampa Bay, Florida, are about twice as high. Extensive seasonal sampling in Mississippi Sound indicates fluctuations but no clear-cut seasonal trends other than a possible relationship between infections and salinity. As C. nebulosus increases in length, the prevalence of infections, but not the intensity, increases. This finding suggests an immune response to challenge infections. No fish less than 140 mm SL and relatively few less than 250 mm SL revealed infections, suggesting either the unavailability of the intermediate host to young fish or the ultimate death of most young infected individuals. Based on condition coefficients and liver-weight analysis, no apparent detrimental effect on infected, moderately-heavy adult fish occurred. Infections primarily involve the middle of a fillet or the region adjacent to the vertebral column below the dorsal fins and cause an esthetically displeasing product and consequently depress economically the trout fishery. Relatively more male than female fish harbored worms, but the significance of that finding is questioned.

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Marine aspidogastrids (Trematoda) from fishes in the northern Gulf of Mexico.

Of the aspidogastrids Multicalyx cristata, Lobatostoma ringens, Cotylogaster basiri, and C. dinosoides sp. n., the last two had not been previously known from the Gulf of Mexico. The latter differs from other members of its genus by having relatively large equatorial marginal alveoli in comparison to those at the anterior and posterior ends of the holdfast. It also possesses extensive transverse musculature connecting opposed lateral alveoli. New host records are included for all four species, and we report preadults of what appear to be the first two species.

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Two new zoogonid digenea from deep-sea fishes in the Gulf of Panama.

Panopula cavernossa gen. et. sp. n. from the intestine of the brotulid Enchelybrotula (?) paucidens differs from other members of the Steganodermatinae by having testes near the anterior of the acetabulum, a posttesticular ovary, and a postequatorial acetabulum. Two related species are transferred to the genus Brachyenteron as B. pycnorganum comb. n. and B. spinosum comb. n. Neosteganoderma gillissi sp. n. from the synaphobranchid eel Synaphobranchus bathybius differs from N. glandulosum and N. polymixiae, the most similar species, because conspicuous glandular cells envelop the esophagus and pharynx, others about the genital atrium occur in elongated sacs, epithelium is lacking at the cecal bifurcation, and the cirrus sac is straight. We establish N. infundibulum comb. n. and expand Steganodermatinae to include Brevicreadium congeri and Hudsonia agassizi.

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A redescription of Crassicutis archosargi, a digenean exhibiting an unusual tegumental attachment.

The homalometrine Crassicutis archosargi from the northern Gulf or Mexico is redescribed, and some related digeneans are discussed. Numerous unidentified refractile bodies occurred in the tegument and other tissues of a few specimens of C. archosargi, and an intimate relationship between the parasite and its piscine host resulting from a modified tegument is reported for others. Binding by the described adhesive tegument increases the number of known ways digeneans attach to their hosts. Several specimens also harbored a histozoic myxosporidan in several tissues and a flagellate, Hexamita sp., in their ceca.

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Thynnascaris reliquens sp. n. and T. habena (Linton, 1900) (Nematoda: Ascaridoidea) from fishes in the northern Gulf of Mexico and eastern U.S. seaboard.

Thynnascaris reliquens sp. n. is described from the type host, the sheepshead, Archosargus probatocephalus (Walbaum), and other fishes of the northern Gulf of Mexico and southern Florida, including the Gulf toadfish, Opsanus beta (Goode and Bean); the spiny boxfish, Chilomycterus schoepfi (Walbaum); the slippery dick, Halichoeres bivittatus (Bloch); and the Atlantic croaker, Micropogon undulatus (Linnaeus). Its salient characters are: length up to approximately to 12.5 cm; lips broad, with pedunculate pulp and equatorially constricted flanges; esophagus 8 to 12% and spicles 3 to 6% of body length; preanal and postanal papillae up to 33 and 6 pairs, respectively. In the type host, some adults attained a considerably greater size than in other hosts, and their labial morphology changed as the maximum length was approached. Thynnascaris habena is redescribed from the oyster toadfish, Opsanus tau (Linnaeus), its type host, on the basis of examination of specimens collected from Massachusetts, Virginia, and Georgia. Thynnascaris melichthysi (Olsen, 1952) and T. ogcocephali (Olsen, 1952) are transferred from the genus Contracaecum as new combinations.

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Thynnascaris rhacodes sp. n. (Nematoda: Ascaridoidea) in fishes from the Israeli Mediterranean coast.

Thynnascaris rhacodes sp. n. infects Pelates quadrilineatus, Solea vulgaris, Boops boops, Lithognathus mormyrus, Obleida melanura, Diplodus vulgaris, D. sargus, and Sparus auratus from the eastern Mediterranean Sea. Unique in that the cuticle on the female tail is wrinkled, the ascaridoid is further characterized by possessing 27 to 35 precloacal papillae, a body length of 11 to 85 mm, similar spicules 3 to 6% of body length, a length-ratio of intestinal cecum to ventricular appendage of 1 : 1 to 5, and lips longer than wide.

Animals↗